Tracking servo system with a variable equalizing characteristic
US5056074A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1989 |
| Grant date | Oct 8, 1991 |
| Priority date | — |
| Expiry date | Apr 7, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S358/907
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A tracking servo system for use in a disc player having a pickup, for playing an information recording disc having a recording track, the tracking servo system comprises an equalizing circuit for compensating for the frequency characteristic of the tracking error signal for the tracking servo operation, the equalizing circuit means performing a compensating operation in accordance with a predetermined compensation characteristic during a normal playback of the recording disc. The system is provided with a control device for varying coefficients determining the compensation characteristic of the equalizing circuit so that the compensation characteristic has a phase margin in a middle frequency range larger than a corresponding phase margin in the predetermined compensation characteristic upon closure of the tracking servo loop, and a middle frequency gain of the equalizing circuit means is gradually increased with time until the compensation characteristic equals the predetermined compensation characteristic when a predetermined time period elapses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.